Molecular structure and vibrational spectra of 1,3-bis(4-piperidyl)propane by quantum chemical calculations

The infrared and Raman spectra of 1,3-bis(4-piperidyl)propane molecule have been recorded between 4000-400 cm−1 region and 3500-150 cm−1 region, respectively. The vibrational frequencies of the molecule are investigated. The molecular geometry and vibrational frequencies of 1,3-bis(4-piperidyl)propane (also named 4,4′-trimethylenedipiperidine (TMDP)) in the ground state have been calculated by using density functional methods (B3LYP and BLYP) with 6-311 G(d,p) and 6-31 G(d) as basis sets. The comparison of the observed fundamental vibrational frequencies of 1,3-bis(4-piperidyl) propane and calculated results by density functional B3LYP and BLYP methods indicates that B3LYP is superior to the scaled BLYP approach for molecular vibrational problems.